A total of £15 billion is being invested to create 1,300 extra miles of lanes up until 2020.
The study will explore the best way to make further improvements to help the economy grow between 2020 and 2025.
It is one of six strategic studies the Department for Transport has commissioned, and work is already underway on the other five.
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WSP Parsons Brinckerhoff, Steer Davies Gleave and GL Hearn have been appointed to complete the project.
Road Minister Andrew Jones said: "We are making a £15 billion investment in our roads – the biggest in a generation – to deliver better journeys and put the infrastructure in place for our economy to grow.
"We have a long-term plan for Britain so we are carrying out 6 strategic studies to decide what further improvements we can make. We are looking at this section of the M25 as it is one of the busiest sections of the road network."
The strategy is due to be completed by the end of 2016.
The other five studies are:
• Northern Trans-Pennine.
• A66 and A69 corridors; Trans-Pennine tunnel - linking Manchester to Sheffield.
• Manchester north-west quadrant.
• M60 from junctions 8 to 18; A1 east of England.
• M25 to Peterborough and the Oxford to Cambridge expressway.
(LM)
